The present invention relates to an instantly erectable access barrier, especially for roadways.
The vulnerability of many buildings, especially those housing government and military personnel to terrorist attacks, is of major concern. Despite the presence of guards and check points, it may be possible for a suicidal terrorist to drive an explosive-laden vehicle past the check point and directly to the building, whereupon a detonation can inflict serious damage to life and property.
It would be possible to position barriers in the roadway, but barriers of sufficient size and strength for resisting a large onrushing truck would be relatively cumbersome to maneuver and would interfere with normal traffic flow.
A terrorist barrier proposed in Terio U.S. Pat. No. 4,576,507 is normally disposed below-ground and intended to be rapidly raised. The barrier comprises a plurality of horizontal cables, the ends of each cable mounted to shock absorbers. The cables and shock absorbers are mounted on I-beams which travel vertically in tracks implanted in the ground. The barrier can be raised by a winch, counterweight system, or explosive means which lifts the I-beams, shock absorbers and cables.
It will be appreciated that a terrorist barrier which is normally disposed below ground must be capable of being raised very rapidly in order to be capable of stopping a quickly advancing vehicle. Therefore, it would be desirable to minimize the overall weight of the risible portion in order to promote a rapid ascent thereof. A barrier in which I-beams and shock absorbers must be raised, may not be capable of sufficiently rapid ascent to be dependable in all situations.